A New General Fatigue Limit Diagram and Its Application of Predicting Die Fatigue Life during Cold Forging

Traditional fatigue fracture theory and practice focus principally on structural design. It is thus too conservative and inappropriate when used to predict the high-cycle fatigue life of dies used for metal forming, especially cold forging. We propose a novel mean stress correction model and diagram to predict the high-cycle fatigue lives of cold forging dies, which focuses on the upper part of the equivalent fatigue strength curve. Considering the features of die materials characterized by high yield strength and low ductility, a straight line is assumed for the tensile yield line. To the contrary, a general curve is used to represent the fatigue strength. They are interpolated, based on the distance ratio, when finding an appropriate equivalent fatigue strength curve at the mean stress and stress amplitude between the line and curve. The approach is applied to a well-defined literature example to verify its validity and shed light on the characteristics of die fatigue life. The approach is also applied to practical forging and useful qualitative results are obtained.     

Acute esophageal obstruction after ingestion of psyllium seed husk powder: A case report

BACKGROUNDBezoar is a mass of hardened external material found in the gastrointestinal (GI) tract. It may form anywhere in the GI tract, but esophageal bezoar is rare because of the short esophageal transit time. Psyllium seed husk is an indigestible natural derivative that is widely used as an herbal laxative. Herein, we report a case of acute esophageal obstruction caused by a bezoar after ingestion of psyllium seed husk powder.CASE SUMMARYA 76-year-old male with Parkinson''s disease visited the emergency department with swallowing difficulty approximately 10 h after ingesting psyllium seed husk powder. Symptoms began a few hours after ingestion and progressed to severe dysphagia. There were no abnormal findings on simple radiography. However, a computed tomography scan revealed an approximately 2.0 cm × 2.5 cm mass located near the gastro-esophageal junction. After grinding, the mass was removed using an endoscopic capture net. Esophageal bezoars may cause life-threatening complications. Patients with Parkinson''s disease may have esophageal motility dysfunction, which may increase esophageal transit time. Since our patient had Parkinson''s disease, this effect may have contributed to the formation of the bezoar.CONCLUSIONAttention should be paid to using bulk-laxatives, and an appropriate specified regimen will be needed when marketed as a dietary supplement.     

Prognostic value of complete metabolic response on 18F-FDG-PET/CT after three cycles of neoadjuvant chemotherapy in advanced high-grade serous ovarian cancer

ObjectiveWe investigated the prognostic value of complete metabolic response (CMR) on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) after 3 cycles of neoadjuvant chemotherapy (NAC) in advanced high-grade serous ovarian cancer (HGSC).MethodsPET/CT at baseline and after 3 cycles of NAC were performed; peak standardized uptakes were measured. PET parameters were compared with NAC parameter: cancer antigen-125 (CA-125) normalization before interval debulking surgery (IDS) and chemotherapy response score (CRS) to predict platinum-sensitivity. Kaplan-Meier analysis was used to determine correlations between PET parameters and survival. Prognostic factors were obtained by multivariate Cox regression analysis.ResultsBetween 2007 and 2020, 102 patients were recruited: 19 (18.6%) were designated as CMR group and 83 (81.4%) as non-CMR group. CMR after 3 cycles of NAC showed the highest accuracy in predicting platinum-sensitivity (area under the curve [AUC]=0.729; 95% confidence interval [CI]=0.552–0.823; p=0.017), compared with CA-125 normalization before IDS (AUC=0.626; 95% CI=0.542–0.758; p=0.010) and CRS (AUC=0.613; 95% CI=0.490–0.735; p=0.080). CMR demonstrated better prognosis than non-CMR in progression-free survival (PFS) (median PFS, 23.9 months vs. 16.4 months; p=0.021) and overall survival (OS) (median OS, not reached vs. 69.7 months; p=0.025). In multivariate analysis, CMR was associated with a lower risk of recurrence (adjusted hazard ratio [aHR]=0.50; 95% CI=0.27–0.92; p=0.027) and death (aHR=0.23; 95% CI=0.05–0.99; p=0.048).ConclusionCMR after 3 cycles of NAC can be a prognostic factor for both recurrence and death in advanced HGSC.     

Magnetic resonance cerebral metabolic rate of oxygen utilization in hyperacute stroke patients

The purpose of this study was to explore the feasibility of obtaining magnetic resonance-measured cerebral metabolic rate of oxygen utilization (MR-CMRO(2)) in acute ischemic stroke patients. Seven stroke patients were serially imaged: 4.5 +/- 0.9 hours (tp1), 3 to 5 days (tp2), and 1 to 3 months (tp3) after symptom onset. Diffusion-weighted, perfusion-weighted, and multiecho gradient-echo/spin-echo images were acquired; cerebral blood flow and oxygen extraction fraction maps were obtained from which CMRO(2) was calculated as the product of cerebral blood flow and oxygen extraction fraction. The final infarct lesions obtained from tp3 T2-weighted images and the "penumbra" obtained from the tp1 perfusion-weighted image-defined lesion were coregistered onto tp1 CMRO(2) maps. CMRO(2) values in the region of brain that eventually infarcted were reduced to 0.40 +/- 0.24 of the respective region on the contralateral hemisphere. The "salvaged penumbra" defined by the area of mismatch between the final infarct and the tp1 perfusion-weighted lesion demonstrated an average CMRO(2) value of 0.55 +/- 0.11 of the contralateral hemisphere. Although our results are preliminary and require further evaluation, the ability to obtain in vivo measurements of MR-CMRO(2) noninvasively potentially can provide information for determining brain tissue viability in acute ischemic stroke patients.     

Combined Endovascular and Microsurgical Procedures as Complementary Approaches in the Treatment of a Single Intracranial Aneurysm

Objective

Both endovascular coil embolization and microsurgical clipping are now firmly established as treatment options for the management of cerebral aneurysms. Moreover, they are sometimes used as complementary approaches each other. This study retrospectively analyzed our experience with endovascular and microsurgical procedures as complementary approaches in treating a single aneurysm.

Methods

Nineteen patients with intracranial aneurysm were managed with both endovascular and microsurgical treatments. All of the aneurysms were located in the anterior circulation. Eighteen patients presented with SAH, and 14 aneurysms had diameters of less than 10 mm, and five had diameters of 10-25 mm.

Results

Thirteen of the 19 patients were initially treated with endovascular coil embolization, followed by microsurgical management. Of the 13 patients, 9 patients had intraprocedural complications during coil embolization (intraprocedural rupture, coil protrusion, coil migration), rebleeding with regrowth of aneurysm in two patients, residual sac in one patient, and coil compaction in one patient. Six patients who had undergone microsurgical clipping were followed by coil embolization because of a residual aneurysm sac in four patients, and regrowth in two patients.

Conclusion

In intracranial aneurysms involving procedural endovascular complications or incomplete coil embolization and failed microsurgical clipping, because of anatomical and/or technical difficulties, the combined and complementary therapy with endovascular coiling and microsurgical clipping are valuable in providing the best outcome.     

Suppression of the jaw-opening reflex by periaqueductal gray stimulation is decreased by paramedian brainstem lesions

Electrical stimulation of the midbrain periaqueductal gray region (PAG) suppresses the tooth pulp-evoked jaw-opening reflex (TP-JOR). In the present study the pathways that mediate this suppression were investigated by placing brainstem lesions in lightly anesthetized cats. Parasagittal lesions that interrupted the afferent and efferent connections of the medullary and pontine raphe nuclei attenuated (but did not abolish) suppression of the TP-JOR evoked by PAG stimulation. This result provides further evidence that medial brainstem structures partially mediate the effects of PAG stimulation in the trigeminal system.     

Impact of diabetes status on immunogenicity of trivalent inactivated influenza vaccine in older adults

Individuals with type 2 diabetes mellitus experience high rates of influenza virus infection and complications. We compared the magnitude and duration of serologic response to trivalent influenza vaccine in adults aged 50–80 with and without type 2 diabetes mellitus. Serologic response to influenza vaccination was similar in both groups: greater fold‐increases in antibody titer occurred among participants with lower pre‐vaccination antibody titers. Waning of antibody titers was not influenced by diabetes status.